Ewch i’r prif gynnwys
Ake Fagereng

Yr Athro Ake Fagereng

Athro mewn Daeareg Strwythurol

Ysgol Gwyddorau'r Ddaear a'r Amgylchedd

Email
FagerengA@caerdydd.ac.uk
Telephone
+44 29208 70760
Campuses
Y Prif Adeilad, Ystafell 2.09, Plas y Parc, Caerdydd, CF10 3AT
Users
Ar gael fel goruchwyliwr ôl-raddedig

Trosolwyg

Interests 

The broad field of structural geology as applied to understand rock deformation at all scales in multiple settings, with focus on: Earthquake Geology; Fault Rocks; Hydrothermal Vein Systems; Rheology of Polyphase Materials; Geological Controls on the Seismic Style of Active Faults; Melanges; Microstructures and Deformation Mechanisms; Subduction Zones; Oceanic Transform Faults; Continental Rifts

Detailed information of research activities, and general updates on research plans and ideas, can also be found on my external research web pages: http://akefagereng.wordpress.com

Cyhoeddiad

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

Articles

Book sections

Conferences

Ymchwil

Rwy'n ddaearegwr strwythurol, ac mae fy ymchwil yn seiliedig ar arsylwadau o ddiffygion naturiol a pharthau cneifio. Rwy'n rhannu fy ngwaith mewn dwy thema allweddol, y ffordd mae diffygion yn llithro (daeargrynfeydd vs ymgripiad vs arddulliau llithro eraill) a sut mae diffygion yn tyfu ac yn cael eu hailgychwyn. Mae'r ddwy thema hyn yn berthnasol i ble y gall daeargrynfeydd ddigwydd a pha mor fawr y gall digwyddiadau o'r fath fod.

Ymddygiad slip fai

Ar hyn o bryd rwy'n canolbwyntio llawer o'm hamser ar y prosiect MICA a ariennir gan ERC, a ddisgrifiwyd yn ddiweddar yng nghylchgrawn Horizon, ac y mae tudalen prosiect ar gael ar ei gyfer. Mae'r prosiect wedi'i gynllunio i archwilio'r prosesau daearegol sy'n rheoli cyflymder ymadael fai, ac ymddygiad amrywiol namau sy'n darparu ar gyfer anffurfiad tectonig yng nghramen y Ddaear. Mae'r diffygion hyn yn llithro ar gyflymdra o filimetrau y flwyddyn, cyfradd sy'n debyg i dwf ewinedd bysedd, hyd at fetrau yr eiliad, cyfradd sy'n cynhyrchu daeargrynfeydd. Yn ystod y ddau ddegawd diwethaf, mae arsylwadau gan rwydweithiau GPS a seismomedr wedi dangos bod diffygion hefyd yn llithro ar gyfraddau canolradd rhwng yr aelodau terfynol hyn, mewn digwyddiadau a elwir bellach yn 'ddaeargrynfeydd araf'.

Nid yw'r prosesau ffisegol sy'n rheoli cyfradd slipiau fai yn cael eu deall yn iawn. Er enghraifft, ar hyn o bryd nid yw'n hysbys ar hyn o bryd pa mor araf a chyflym y mae daeargrynfeydd yn gysylltiedig.  Mae cwestiynau pwysig o bwysigrwydd cymdeithasol yn cynnwys: Os bydd nam yn profi daeargrynfeydd araf, a all hefyd brofi daeargrynfeydd sy'n niweidiol? Os yw rhannau o nam yn profi daeargryn araf, a yw hyn yn cynyddu (neu'n lleihau) tebygolrwydd daeargryn niweidiol gerllaw? A all daeargrynfeydd arafu gyflymu a dod yn gyflym ac yn niweidiol? Mae prosiect MICA yn ceisio nodi effeithiau trwch parth ffawt, geometreg fewnol a chyfansoddiad. Gwneir hyn trwy waith maes manwl ac astudiaethau labordy o greigiau o barthau nam sy'n agored ar wyneb y Ddaear, neu'n hygyrch trwy ddrilio cefnforoedd. Yn seiliedig ar arsylwadau maes a microscale, rydym yn creu modelau ar gyfer geometreg realistig a mecanweithiau anffurfiad mewn parthau ffawtio mawr. O'r modelau hyn, rydym yn nodi newidynnau sy'n rheoli cyflymder llithro, ac yn caniatáu llithro ar ystod o gyflymderau. Mae'r rhagdybiaethau hyn yn cael eu profi gan arbrofion anffurfiannau rhifiadol a labordy.

Casglwyd samplau allweddol yn ystod Taith IODP 375 i ymyl tansugno Hikurangi Seland Newydd. Gallwch ddarllen fy mlog bwrdd llongau ar yr hyn y gallai drilio cefnfor ei ddweud wrthym am ddaeareg a mecaneg parth ffawt. Rydym wedi cyhoeddi the geology of the Pāpaku fault, a allai gynnal llithriad araf gweithredol, ac ar sut y gall gwaddodion heterogenaidd a thopograffeg llawr y môr reoli ymddygiad slip byrdwn subduction. Mae fy erthygl yn The Conversation yn esbonio peth o'r ymchwil hon, ac mae'r erthygl hon yn Futurum Careers yn darparu adnodd addysgol ar weithio fel daearegwr bwrdd llongau.

Mae canlyniadau allweddol eraill y prosiect hwn yn cynnwys

  • Mae ymhelaethu straen yn digwydd o fewn parth cneifio heterogenaidd a gellir ei fesur gyda model rhifiadol o barth cneifio gludiog dau gam, fel y'i cyhoeddwyd gan Beall et al yn GRL (2019), a'i gymhwyso ymhellach i ddigwyddiadau llithro araf wrth gynnwys toriadau yn y model, fel gan Beall et al. yn G-Cubed (2019) .
  • Gall isdynnu crwst cefnforol, os caiff ei hydradu a'i newid, fod mor wan â'r gwaddodion ar ei ben, fel yr eglurwyd gan Tulley et al in Science Advances (2020).
  • Efallai mai'r rhwydweithiau gwythiennau trwchus a welir yn gyffredin mewn prismau cronedig exhumed yw cyfanswm, effaith integredig llawer o benodau torri lleol, sy'n cael eu gyrru gan hylif mewn ystod gymharol fach o ddyfnder - yn debyg i tremor mewn parthau is-sugno gweithredol, fel y trafodwyd yn seiliedig ar y Kuiseb Schist yn Fagereng et al. (Daeareg, 2018).
  • Er mai phyllosilicadau yn aml yw'r elfen wannaf o barth cneifio, efallai na fyddant yn cael eu cydgysylltu ar straenau uchel, ac yn lle hynny gellir rheoli anffurfiad gan y cynhyrchion adwaith graen mân sy'n anffurfio'n hawdd trwy trylediad - fel Stenvall et al. (2019) yn esbonio yn eu herthygl GRL 'Weaker than weakest'.

Diffygion, twf fai, ac ail-ysgogi bai

Rwyf bellach wedi bod yn gweithio yn System Hollti Dwyrain Affrica ers sawl blwyddyn, yn enwedig yn y de, amagmatig, Hollt Malawi. Un pwynt o ddiddordeb yma yw sut y gall strwythurau hynafol reoli twf fai a daeargrynfeydd. Mae'r gwaith hwn wedi'i ariannu gan Gronfa Ymchwil Heriau Byd-eang yr EPSRC, ym mhrosiect PREPARE - cydweithrediad rhwng Peirianneg a Gwyddorau Daear ym Mhrifysgolion Bryste a Chaerdydd, gyda'r nod o wella gwytnwch daeargrynfeydd yn Nwyrain Affrica.

Er bod prosiect Malawi yn archwilio ffin plât graff, mae gen i ddiddordeb hefyd mewn diffygion sy'n ffurfio ymhell o ymylon platiau, fel namau diwedd ac ôl-rewlifol sy'n cynnal daeargrynfeydd mewn ymateb i gilio rhewlifoedd. Rwy'n PI o'r prosiect DAFNE (Drilio Diffygion Gweithredol yng Ngogledd Ewrop) sy'n ceisio drilio i mewn i'r nam Pärvie ôl-rewlifol yng ngogledd Sweden. Cefnogir y prosiect hwn gan gronfeydd o'r Rhaglen Drilio Gwyddonol Cyfandirol Ryngwladol (ICDP).

Addysgu

I am a fellow of the Higher Education Academy. I teach across the undergraduate programmes in the School of Earth and Environmental Sciences, primarily supporting Geology, Exploration and Resource Geology, and Environmental Geoscience students.

My teaching is focused on structural geology, but also larger scale tectonics and geodynamics, and BSc and MSci Dissertation Projects. You're also likely to find me teaching in the field.

During my time in Cardiff, I have been involved in teaching the following:

  • Introduction to Geological Maps, Sections, and Structures (year 1)
  • Structural Geology (year 2) and Structural Techniques (year 3)
  • Geodynamics (years 3 and 4)
  • Residential field courses on structural geology, including focus on structural controls on mineral deposits (in Cornwall for year 2 and in north Wales for year 3) and mapping training in Spain at the end of year 2. I have also participated in teaching the final year field course (in Cyprus).
  • I was Director of Fieldwork from 2015 to 2018.

Prior to working in Cardiff, I was a Senior Lecturer in the Department of Geological Sciences at the University of Cape Town. There, I taught structural geology at BSc and BSc(Hons) level, geology to civil engineers, and supervised several BSc(Hons) and MSc projects.

Bywgraffiad

Education

1999-01          International Baccalaureate, Li Po Chun United World College of Hong Kong
2002-05           University of Cape Town, BSc(Hons) with distinction
2006-09           Otago University, PhD: 'Subduction-Related Fault Processes: Ancient and Active'

Academic Career

2006-09         Teaching Assistant, Otago University
2010-14         Lecturer - Senior Lecturer, Department of Geological Sciences, University of Cape Town
2014-             Honorary Research Associate, Department of Geological Sciences, University of Cape Town
2014-             Lecturer, School of Earth & Ocean Sciences, Cardiff University, UK

Affiliations

- American Geophysical Union
- Geological Society of America
- Geological Society of New Zealand
- Geological Society of Norway
- Seismological Society of America

External Activities

- Member of the Editorial Advisory Board, Journal of Structural Geology (2014- )
- Corresponding Editor, Special Publications of the Geological Society of London volume 359.
- Session Convenor, AGU Fall Meeting, 2013 and 2014.
- Member of Accreditation Committee, Faculty of Science, University of Cape Town (2011-2013)
- Undergraduate External Examiner (Rhodes University, South Africa, 2011-13)
- MSc Examiner (University of the Western Cape, South Africa)

Research Grants

Principal Investigator on a South African National Antarctic Programme grant (2012-2015) to study shear zones in the Maud Belt of Dronning Maud Land, East Antarctica, and a number of University of Cape Town Carnegie Foundation Research Development Grants (2010-2014) to work on structures in the Damara Belt, Namibia. Continuing Inkaba yeAfrica funded, long-term monitoring of intraplate seismicity in the Western Cape, South Africa (2011 onwards). Co-investigator on a New Zealand Marsden grant to study controls on creeping vs. locked segments of the Hikurangi Margin (PI: Susan Ellis, GNS Science). NRF Incentive Funding for Rated Researchers has funded initial work on fault systems in the East African Rift (2014), to be continued with student support from the GW4+ Doctoral Training Programme.

Research Student Supervision

PhD
- Valeria Bilancia (2012 - present, registered at the University of Cape Town): Geodynamics and continental extension in the East African Rift System - origin and evolution of the Turkana Depression
- Michael S. Hodge (2014 - ): Development, deformation style, and seismic hazard of large normal faults

MSc
- David McGibbon (Graduated, 2014, UCT): Shear zones of the Maud Belt, Antarctica - Kinematics and deformation mechanisms. Now at Umvoto Africa.
- Matthew Hodge (Graduated with distinction, 2013, UCT; GSSA award for top MSc thesis in South Africa, 2013): Neotectonics of the Southern Cape. Now at Remote Exploration Services.
- Clayton Cross (Graduated with distinction, 2013, UCT): Metamorphic history of the Matchless Amphibolite, Damara Belt, Namibia (co-supervised with Johann Diener).
- Louis Smit (passed pending corrections, UCT): Microseismic monitoring of the Ceres-Tulbagh region, Western Cape, South Africa.
- Sukey Thomas (awaiting examination results, UCT): Melt migration as recorded in Sverdrupfjella, Maud Belt, Antarctica (co-supervised with Johann Diener).
- Kaylan Hamel (Part-time, in progress, UCT): Fluid-rock interaction in the Colenso Fault Zone, Saldania Belt, South Africa. Employed at MSA.
- Nondumiso Ntombela (Part-time, in progress, UCT): Fault-seal analysis and hydrocarbon potential of the West Coast basins of South Africa. Employed at PetroSA.
- Michael Hartnady (in progress, UCT): Deformation history of the Southern Marginal Zone, Damara Belt, Namibia.
- Gregory Byrnes (in progress, UCT): Structural and metamorphic history of Sverdrupfjella, Antarctica (co-supervised with Johann Diener).

13 BSc(Hons) students at the University of Cape Town, including two prize-winning projects: Michael Hartnady (Structural Geology of the Southern Marginal Zone in Gaub Canyon, Namibia; GSSA award for top Honours project in southern Africa, 2013), and Sean Rennie (Strain distribution in the Kuckaus Mylonite Zone, Namibia; First runner-up in the Midland Valley Structure Competition, Undergraduates, 2012).

Anrhydeddau a dyfarniadau

  • American Geophysical Union, Geophysical Research Letters, Editor's Citation for Excellence in Refereeing (2013)
  • President's Award, National Research Foundation, South Africa (2013)
  • Elsevier Young Scientist Award (2013)
  • Claude Leon Foundation Merit Award for Young Lecturers (2012)
  • University of Cape Town College of Fellows' Young Researcher Award (2012)

Aelodaethau proffesiynol

  • American Geophysical Union
  • Geological Society of America
  • Geological Society of London
  • Geological Society of Norway

Pwyllgorau ac adolygu

  • Associate Editor, Geophysical Research Letters (2015 - present)
  • Member of the Ramsay Medal committee, Tectonics Studies Group of the Geological Society of London (2016, 2017 [chair], 2018)
  • Member of the Editorial Advisory Board, Journal of Structural Geology (2014 - present)
  • Accreditation Committee, University of Cape Town (2011 - 2013)
  • Journal reviewer, Earth and Planetary Science Letters, Earth Planets Space, G-Cubed, Geofluids, GSA Bulletin, GSA Special Papers, Geological Society of London Special Publications, Geology, Geophysical Research Letters, Gondwana Research, International Geology Reviews, Journal of Geophysical Research, Journal of Marine and Petroleum Geology, Journal of Structural Geology, Journal of the Geological Society of London, Nature Communications, Nature Geoscience, Precambrian Research, Pure and Applied Geophysics, Science China, South African Journal of Geology, Tectonics, Tectonophysics
  • Grant reviewer, National Commission for Scientic and Technological Research (Chile),National Geographic, National Research Foundation (South Africa), National Science Foundation (USA), Natural Environment Research Council (UK), and Netherlands Organisation for Scientic Research

Meysydd goruchwyliaeth

I am interested in supervising PhD and Masters students. See past projects below for the sort of topics I tend to supervise, which are in the general areas of

  • Structure and mechanics of subduction zones
  • Hydrothermal vein systems
  • Fault zone structure
  • Development and rheology of shear zones
  • Links between geological and geophysical observations

I am also happy to co-supervise structural geology elements of broader projects.

Current students

  • Sara de Caroli - Failing under pressure: exploring the frictional-viscous transition in cold subduction zones
    • Funded by a Cardiff University College of Physical Sciences and Engineering Studentship and the European Reseach Council

Goruchwyliaeth gyfredol

Sara De Caroli

Sara De Caroli

Myfyriwr ymchwil

Prosiectau'r gorffennol

Myfyrwyr PhD blaenorol a'u teitlau prosiect (gyda chysylltiadau â'u traethodau ymchwil):

Myfyrwyr blaenorol MESci a'u teitlau prosiect:

  • Oliver May (cyd-oruchwylio gyda Lucy Lu) - Rhaniad anffurfio ar ffiniau plât cydgyfeiriol oblique
  • Manon Carpenter (cyd-oruchwylio gyda Jack Williams) - Sut mae diffygion yn tyfu mewn rhwygiadau cyfandirol? Cipolwg ar ddadansoddiad microstrwythurol o ddiffygion yn ne Malawi
  • Paul Edwards (cyd-oruchwylio gydag Adam Beall) - Beth sy'n rheoli'r amrywiad mewn maint daeargryn rhwng parthau cipio, gyda seamountau wedi'u tynnu?
  • Stephen James (cyd-oruchwylio gydag Adam Beall) - Pan fydd diffygion yn dod yn barthau cneifio: Modelu'r trawsnewidiad ffrithiannol-gludiog 
  • Aled Evans - Llif hylifol a mineraleiddio ar hyd parthau ffawtio hirhoedlog ac wedi'u hailactifadu: Enghraifft o Fynydd Carmel Head, Ynys Môn, Gogledd Cymru
  • Dylan Ingman - Straen a phrosesau lleoleiddio straen ym mylonitau Belt Maud